We have the 7.2 v 3000 mAh batteries. I have two questions that I want to get your opinions on.
First, once a battery is charged up and I take it off of the charger, will you lose charge overnight? My students seem to think their batteries are doing this. I typically have the students place their batteries on charge before they leave class. If, before I leave the building they are charged, I will disconnect the battery from the charger. Some have said they are getting a low battery indication the next day. Didn’t know if this is just how things are or not?
Second, is it safe the leave the batteries plugged into the chargers overnight, even though they say the batteries are at full charge?
A healthy battery will not lose significant charge overnight.
I’ve left batteries plugged in overnight on lots of occasions. They seem fine afterwards, and some are five years old.
You’re not the first person to post about battery issues recently, it seems like over the last few months there have been some bad ones. If you bought them recently, see if you can confirm that they’re losing charge, and if so contact VEX to see if they know about an issue or will replace them.
They should be fine, however if a team just about completely drained a battery, they may not have time to recharge before you pull the plug. The charger MAY be faulty, but likely not. I’ve never had any problems with batteries from any walk of life charging for long periods of time. (Unless they’re from Samsung :p)